Posted on 12/05/2007 11:46:58 AM PST by Red Badger
The Coates Spherical Rotary Valve Engine is the most advanced in the world. A conventional piston engine ignites the fuel and air mixture in the combustion cycle and evacuates the gas by-products in the exhaust cycle. These cycles occur thousands of times per minute per cylinder. Through the rotation of the camshaft, a spring-loaded poppet valve opens to enable the fuel and air mixture to enter the firing chamber during the induction stroke. The camshaft then closes the intake valve during the compression and combustion stroke of the cylinder and opens a second spring-loaded valve to vent the cylinder after ignition. These gases then enter the exhaust manifold.
The parts required for this conventional spring-loaded valve assembly include items such as springs, cotters, guides, rockers, shafts and the valves themselves. The valve operates in a vertical position in the cylinder head such that a downward movement opens the valve and allows the introduction or evacuation of gas from the chamber.
The weakest link in the conventional engine has been the limited effectiveness of the poppet valve. The Coates engine replaces the poppet valve with a spherical rotary valve, thereby creating more efficient and powerful combustion and compression stokes.
The spherical rotary valve system is made up of spheres rotating on a shaft sandwiched between a split head. These spheres are either chain or belt driven via the crankshaft, much like an overhead camshaft. Each sphere rotates against a matching seal between it and the piston, one for intake and one for exhaust. The spheres have cavities and ports machined into them for the induction of fuel and air on the intake stroke, and the evacuation of fired gases on the exhaust stroke. This design performs exactly the same function as poppet valves, but the design eliminates the poppet valves, valve springs, guides, camshaft, pushrods, rocker arms and other smaller parts. The Coates engine operates with over 100 fewer parts than convention engines.
In addition, the spherical rotary valve combustion engine utilizes a proprietary seal at the intake and exhaust ports of the cylinder to prevent pressure leakage. This two-piece seal contacts the peripheral surface of the rotary valve and utilizes the compression and expansion of the fuel and air mixture to create a gas-tight seal with the valves. The lubrication of the rotary valve assembly is accomplished by bronze shaft bearings. Advantages of the Engine:
The spherical rotary valve combustion engine possesses several significant advantages over the conventional poppet valve assembly. The benefits include the following:
Lower Emissions - Conventional engines run hot due to their inability to disperse heat from the firing chamber. The resulting high temperatures break down the oil used to lubricate the valves and produce oxides of nitrogen as well as the usual hydrocarbons. In addition, oil entering the combustion chamber through the intake valve is continually redirected back into the induction system due to pressure provided by the exhaust valve. This process compounds the problem of oil burning in a conventional engine. The Coates engine avoids the problem of oil burning by requiring no oil lubricants for the valves. Moreover, the rotation of the spherical valve heads reduces engine temperature by constantly changing the surface exposed to combustion heat. By eliminating the use of oil in valve lubrication and lowering operating temperature, the Coates engine emits significantly lower levels of pollutants than a conventional engine.
Reduced Fuel Requirements - Conventional engines lose power through friction and pumping. The spherical rotary valve assembly virtually eliminates engine friction and pumping losses. As a result of this operating efficiency, engines incorporating the spherical rotary valve design offer higher fuel economy than do conventional engines.
Reduced Lubrication Requirements - The use of seals and shaft bearing make oil lubrication of the valve heads unnecessary and lower the overall oil requirements of the Coates engine in comparison to a conventional engine. Without the component wear that characterizes typical poppet valve systems, engines using the spherical rotary valve design also produce fewer metallic particulates. As a result of these factors, the spherical rotary valve engine can realize longer maintenance intervals than conventional engines.
Increased Engine Power - The comparative efficiencies of the spherical rotary valve combustion engine have enabled engine speeds of 14,850 RPMs. In addition, the spherical rotary valve design can accommodate markedly higher compression ratios than conventional engines. The rotary design provides these exceptionally higher compression ratios with no detectable detonation when utilizing fuels of lower octane ratings. These factors, coupled with the ability of the rotary valve head to deliver more fuel to the combustion chamber than the poppet valve, makes the Coates design especially well suited for more powerful engines.
Reduced Engine Noise and Vibration - The spherical rotary valve combustion engine virtually eliminates mechanical clatter, one of the sources of engine noise. Mechanical clatter is a by-product of the wearing of components, inadequate lubrication, and components working themselves out of adjustment. The operation of CIL's prototype engines involves a rotary movement of the valve with uniform acceleration and deceleration of the components. Without the specific stresses and vibrations inherent in a poppet valve assembly, the spherical rotary valve combustion engine runs more quietly than conventional engines.
Alternative Fuel Adaptability - Unlike engines of conventional design, the spherical rotary valve assembly can be fit to almost any internal combustion engine from the single cylinder to the largest marine diesel. In addition, the spherical rotary valve system causes the engine to run far cooler than conventional designs thereby enabling it to utilize lower octane fuels. Conventional poppet valves run hot due to their inability to disperse heat away from the combustion chamber. Hot exhaust valves in the conventional valve train system create "hot spots" which are the primary cause of pre-ignotion unless lead additives are present. Lead-free gasoline requires the use of long-stroke, relatively low compression engines in order to function properly without fuel additives. High compression ratios can be utilized incorporating the Coates more efficient and powerful short-stroke design, while maintaining the desirable characteristics of optimum performance using lead-free gasoline. The design also allows the use of alternate fuels such as methanol and an alcohol mixture. The capability of variable valve timing is a design characteristic that lends itself to alternate fuel compatibility.
Reduced Manufacturing Costs - Utilizing standard production techniques while remaining within acceptable engineering standards and tolerances relating to current production line technology, the design can be manufactured at a substantial savings due to the following factors:
1. Fewer components/Lower costs 2. The number of components required in the manufacture of the design is approximately 29 vs. the l55+ required for conventional valve train designs. 3. All components of the design can be die cast or stamped out. - Assembly time of the design is substantially less than that required for conventional designs, and once assembled, requires no further adjustments. Comparative Analysis:
Emissions tests conducted by an independent EPA-Compliant laboratory in USA have confirmed the superiority of Coates International CSRV engines in producing significantly lower pollutant. The following chart presents the emission results as reported by an independent laboratory which tested two vehicles, one running with stock engine and the second with stock engine retrofitted with Coates CSRV system.
Both vehicles were tested in steady state with the following parameters: • No EGR system • Warm up run on Dynamometer: 30 minutes • Engine temperature: 180 degrees F • Inertia Load: 2,000 pounds • Road horsepower: 13 • Two catalytic converters installed
New Engine Technology PING!..............
bump
What a great idea! It seems that the rotary valves would really shine with a turbo or a supercharger.
I want more numbers and side-by-sides for comparable HP models to the conventional side of the house.
Otherwise, this is intriguing. But I’ve heard the “better mousetrap” argument so many times when it comes to internal combustion engines... I grow weary and wary.
bttt
There’s more info at the website......
This is not the first rotary valve engine...
Let me know when it hits the market, which will probably be never.
Can you imagine a Harley being able to rev like a Kawasaki?
Sheesh. Move over foreign crotch rockets!
I'd be concerned about the long term effects of high temperatures and potential for deformation of these machined cavities and ports in the spherical valves - especially if there is any asymmetry in the design.
One of the nice things about conventional valves is their symmetrical geometry which resist high temperature stresses and radial loads.
I have not seen the schematics or material specs, but in general my concerns relate to the ultimate endurance of an engine like this.
Not technically qualified to offer an opinion but I’ll sure BTT this one. Sounds like an interesting idea.
wow... rotary valves!! Gosh, weren’t those used on the Whippet about 90 years ago?
And to think that they’re brand new technology today!!!! (/sarcasm)
http://www.ianchadwick.com/motorcycles/britbikes/otherr_z.html
“Founded by brothers William and Harold Williamson as a car manufacturer in Coventry in 1899. In 1904 they turned to motorcycles with 456cc single and 726cc twin. Made the first telescopic forks, in 1906 and several other innovations including rotary-valve engines and in 1908 were the first to angle the top tube downward to lower the riding position...”
Interesting comment. One I could have easily made. Apparently it already is on the market. Look at the post above with the link to the motorcycle company.
I was referencing post #11. Noticed there are other links.
Although the number of parts are reduced, wouldn’t there be massive friction between the rotating valving element and the seal, thereby reducing the life of those seals themselves?
The company isn’t doing well on the market.
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